Gardens & Grounds

Vernal Pool at Pattison Woodlands

With a hard, rock bottom and surrounded by forest, this abandoned Rockland-Rockport Lime Company quarry hole became a perfect place for a vernal pool habitat to form. The rock bottom prevents pooling water from snowmelt and runoff to absorb into the ground. The trees surrounding the pool provide shade to prevent the water from evaporating. A constant supply of downed limbs and leaves provides detritus for nutrients and shelter for the creatures that live in the pool.

In early spring, you may hear the “quacking” of wood frogs as they make their mating calls. By April, the pool is filled with the jelly-like egg masses of wood frogs and spotted salamanders. Later in the spring, the pool comes alive as wood frog tadpoles and spotted salamander larvae hatch from their eggs. Predaceous diving beetles, dragon fly larvae, and hellgrammites (Dobson fly larvae) are top predators in the pool, while small amphibious snails, red water mites, caddisfly larvae, and many other unique invertebrate species can be observed in the pool’s waters.

By early autumn, the vernal pool dries up. Certain species of plants thrive in the fertile, damp soil. Falling leaves provide next year’s pool with nutrients and shelter as detrivores break them down on the pool bed. Winter brings snow and ice to the pool. The yearly cycle begins again as late-winter thaws and early spring rains begin to fill the pool back up with water.